StudySite: name of the study site
Nestbox: Unique ID for each nestbox
DateColl: date of egg collection (Julian date)
LayingSeq: laying sequence (1 = first-laid egg)
EggmassFresh: egg mass when the egg is collected (g)
EggmassDefrost: egg mass when the egg is defrost for the analyses (g)
Length: length of the egg (mm)
Width: width of the egg (cm)
Yolkmass: mass of the yolk (g)
Eggshellmass: mass of the eggshell (g)
EggshellThick1: first measure of eggshell thickness (mm)
EggshellThick2: second measure of eggshell thickness (mm)
EggshellThick3: third measure of eggshell thickness (mm)
yolk: whether we managed to collect the yolk or not
ID_egg: Unique ID for each egg
Incubation: whether incubation had started or not


